In recent years, perhaps the most revolutionary development in technology has been the computer. While the fundamental components of a computer's architecture remain unchanged, the capabilities of these individual components have increased exponentially as technology rapidly progresses. Common to most every computer is a processing unit which receives input information and processes this information to generate an output. A computer program instructs the processing unit to perform various tasks, and an associated memory unit is incorporated to store instructions for the processing unit and to hold temporary results that may occur during operation.
Computer memories are used to store a system of on-off codes for access at a later time, and systems accomplish this in a variety of ways, such as through the utilization of magnetic disks, optical devices and the like. Where magnetic disks are concerned, patterns of magnetism are formed on the disks in order to store desired information. A magnetic disk may be in the form of either a floppy disk or an arrangement of hard disks which are permanently enclosed in a disk drive to prevent contamination. The hard disk drive for rigid, magnetic memory disks is akin to a conventional record turntable in that a mechanism rotates the disk and translates a read-write data head across the disk's surface to permit a selected annular track to be accessed.
Data heads are conventionally referred to as "flying" heads because they are not intended to contact the surface of the disk during rotation. Rather, these heads hover over the surface on an air bearing that is located between the disk and the head and which is caused, at least in part, by rotation of the magnetic disk at high speeds. The persisting problem with rigid magnetic memory disks is that asperities, i.e. protrusions on surfaces of the disks, may cause an anomaly when encountered by the data head. These asperities can cause errors in the transfer of information or even damage to the data head during operation. In an effort to alleviate such occurrences, manufactures commonly burnish the surfaces of disks. During the burnishing stage, a burnishing head is mounted in a similar manner relative to the disk as discussed above and operates to smooth out these surface asperities.
The next step in further refining magnetic disks for production is through the use of a glide head. A glide head detects, via proximity or contact, any asperities remaining after the burnishing operation which may come into contact with the data head during use. Glide heads are required to hover and detect asperities which are located above specified flying heights. Thus, glide heads dynamically test the integrity of a disk's surfaces.
To this end, a glide head assembly is utilized which includes a flexure and a glide head device disposed on the flexure. The glide head device, itself, comprises a slider having an air bearing surface that faces the disk's moving surface when in operation and a transducer associated with the slider. The transducer may take on a variety of different configurations and be mounted in a variety of different ways. For example, a piezoelectric transducer may be adhered between the upper surface of the slider and the flexure or adhered to the slider alone, independent of the flexure. My co-pending U.S. application Ser. No. 08/780,634, entitled GLIDE HEAD ASSEMBLY AND TEST DEVICE UTILIZING THE SAME, filed Jan. 8, 1997, relates to a legged piezoelectric transducer which may be mounted to the slider's trailing end surface to project outwardly therefrom. Another alternative is disclosed in my U.S. Pat. application Ser. No. 08/602,209, entitled GLIDE HEAD ASSEMBLY AND METHOD THEREFOR, filed Feb. 15, 1996, which shows that a piezoelectric transducer may also be configured as a flat plate and be sandwiched between the slider and the flexure so as to have an exposed free end portion which projects outwardly from this region.
Irrespective of the particular construction chosen, the crystalline lattice of the piezoelectric transducer is disturbed upon impact of the slider with a surface asperity. This disturbance causes an electronic signal to be sent to a signal processing circuitry. However, the same disturbance also causes a variety of other electronic signals to be sent to the signal processing circuitry. These signals are caused, at least in part, by resonant vibrations of other components in the glide head assembly, as well as inherent noise in the test system. As discussed in my co-pending patent applications, the particular construction of the glide head device is important to obtaining reliable electrical response characteristics during the asperity detection process.
While it is difficult to precisely control these electrical response characteristics, there is also a drawback to the existing construction for sliders used in conventional glide head devices. For the most part, existing sliders are constructed as rigid bodies having an air bearing surface that can take on a variety of different configurations. A widely used slider construction is one in which the rigid body is elongated and includes a pair of spaced apart, elongated rails. Each of the rails has an associated rail surface facing the disk's moving surface and, together, these rail surfaces define the air bearing surface. The air bearing surface is polished or lapped so that it is microfinished to have an Ra value in a range between 5 angstroms and 30 angstroms, where Ra is a roughness parameter known in the art and refers to the arithmetic deviation of a surface's peaks and valleys over a given sampling length. It is desirable to have a slider's air bearing surface polished very smoothly so that the glide head device exhibits desired flying height characteristics during use.
One end of the rigid body is provided with a leading edge ramp so that the slider hovers on an air foil at a desired pitch above the disk's surface. During the asperity detection process, then, most of the slider/asperity impact occurs near the trailing edge of the slider which is necessarily closer to the disk's surface than the leading edge. The trailing edge of the slider, therefore, has a tendency to degrade rather rapidly due to its repeated contact with asperities. Eventually, then, the slider needs to be replaced to avoid jeopardizing response characteristics.
Accordingly, a need exists to provide a new and useful glide head device having improved structural integrity, thereby to reduce degradation during the asperity detection process. There is a further need to provide a new and useful methodology for manufacturing such a slider. The present invention is directed to meeting these needs, among others.